1. Field of the Invention
The present invention relates to a method of recording an image or other information on a thermosensitive recording medium by applying thermal energy to the thermosensitive recording medium with a laser beam.
2. Description of the Related Art
Thermal recording apparatus for applying thermal energy to a thermosensitive recording medium to record an image or other information thereon are in widespread use. For example, a thermal printer having a thermal head composed of a linear array of heating resistive elements is widely used.
In the thermal printer, the heating resistive elements are successively heated depending on the image information to be recorded, thus forming an image as a cluster of pixels. The thermal energy produced by the heating resistive element which is presently being heated is transmitted to a support on which the thermal head is supported. The thermal energy transmitted to the thermal head support adversely affects the formation of a pixel by a succeeding heating resistive element. As a result, the thermal head fails to form an image having a desired density distribution.
Japanese patent publication No. 64-2076 discloses a thermal recording apparatus which is designed to solve the above problem. In the disclosed thermal recording apparatus, the number of pulses to be applied to a heating resistive element that is to be heated presently is controlled in view of the heat information as to those pixels positioned before, above, below, and after the pixel produced by the heating resistive element that is to be heated presently. In this manner, any undue temperature rise of the thermal head support is compensated for to print a high-quality image free of blurs.
Another known thermal recording apparatus is a laser beam recording apparatus which uses a laser beam as a heat source for recording an image at a high speed, as disclosed in Japanese laid-open patent publication No. 62-78964. The laser beam recording apparatus scans a thermosensitive recording medium with an intensity-modulated laser beam in a main scanning direction while the thermosensitive recording medium is being fed in an auxiliary scanning direction, thereby recording an image or other information on the thermosensitive recording medium.
Since the laser beam recording apparatus does not have a plurality of heat sources, it is not necessary to take into consideration the effect of a temperature rise of the heat source as is the case with the thermal recording apparatus. However, the laser beam irradiating the thermosensitive recording medium has a Gaussian thermal energy distribution in its cross section, requiring efforts to be made to remove the effect of the Gaussian thermal energy distribution on those pixels which are positioned adjacent to the pixel that is formed by the laser beam. It is also necessary to take into account the effect of heat conduction on the thermosensitive recording medium.